Although the absolute rate of primary upper extremity deep vein thrombosis (UEDVT) is low, the incidence is increasing due to more widespread use of central venous catheters. Both cancer and use of central venous catheters have been shown to be common risk factors for UEDVT (J Thromb Haemost 2005 Nov;3(11):2471), and a recent systematic review concluded that peripherally inserted central catheters are associated with higher risk of UEDVT than other central venous catheters (Lancet 2013 Jul 27;382(9889):311). Previously, a clinical prediction score has been shown to help predict UEDVT in patients with clinically suspected disease (Thromb Haemost 2008 Jan;99(1):202). A new study evaluates a diagnostic algorithm that uses the clinical prediction score to guide testing with D-dimer and compression ultrasound.

The scoring system gives 1 point each for presence of venous material (such as a catheter), localized pain, and unilateral pitting edema, and subtracts 1 point if there is a plausible alternative diagnosis. For patients who score 1 point or less, the initial test of the algorithm is a serum D-dimer which if negative can rule out a UEDVT. If the D-dimer is elevated, then a compression ultrasound is done. For patients with a score of 2 or 3, the algorithm starts with a compression ultrasound. If that is positive a UEDVT is diagnosed, but if negative a D-dimer test is also obtained to confirm the absence of a UEDVT. Inconclusive results on compression ultrasound were managed with repeat ultrasound and, if necessary, venography. Patients who were classified as having no UEDVT after completing the algorithm had clinical follow-up for 3 months.

A total of 406 patients (mean age 56 years) with suspected UEDVT were enrolled, and 390 patients (96%) had a full workup according to the algorithm. UEDVT was diagnosed by compression ultrasound (done when indicated by the algorithm) in 25%. During clinical follow-up of patients without UEDVT according to the algorithm, UEDVT was subsequently diagnosed in 1.2% of 84 patients initially classified as “likely UEDVT” (including 12 protocol violations), but in none of 162 patients initially classified as “unlikely UEDVT”.

An algorithmic approach to diagnosing lower extremity DVT using a clinical prediction rule, D-dimer testing, and compression ultrasound where indicated has previously been described (J Thromb Haemost 2009 Dec;7(12):2035). These new findings extend the use of a similar diagnostic algorithm to patients with clinical suspicion of UEDVT. Like the previous algorithm, this new algorithm benefits from being relatively simple, quick, and noninvasive. In addition, the similarity of this new diagnostic strategy to an established algorithm may help facilitate its implementation into clinical practice.